The 5.4 engine in my '02 F150 (8K miles) makes what I would describe as a raspy ticking sound. The only time I hear it is when accelerating while the engine is cold. The sound starts around 20-25 mph and disappears around
35-40 mph. The sound is reduced if I back way off on the throttle. There are no unusual noises immediately after a cold start while idling. After a few minutes, when the temperature has come up the sound goes away.If it were because of a bad hydraulic lifter, wouldn't it be noticeable right after starting? Any ideas what this could be and what can be done? I thought about trying different oil (5W-20 is recommended) possibly Mobil 1
5W-30.